Hippocrates said it best: "If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health." It is for precisely this reason that prescribing pills to curb obesity and diet management alone will never tackle the root cause of the public health crisis facing the NHS.

Medicating to reduce obesity is a short-term fix rather than a long-term solution simply because it is a curative measure rather than a preventive one. One of the most effective ways of stemming obesity is to raise people's awareness of the need to balance the "energy in" (the food we eat) with the "energy out" (the activity we do), to create equilibrium - as Hippocrates stated - between our nourishment and our exercise.

It is now accepted wisdom that to optimise the nation's health we need to develop preventive intervention strategies which balance "energy in" with "energy out" and get more people more active, more often.

In 2007 alone, obesity drugs cost the NHS £47.5million (but the government's Information Centre for Health and Social Care puts the real cost of treating obesity and its related illnesses, cardiovascular disease, type 2 diabetes and asthma, at between £990m and £1.2 billion). That same £47.5m could fund 35,000 physical activity referral schemes a year. These 12-week programmes are designed to build participants' weekly activity levels via tailored personal exercise plans during supervised group sessions, which could be held at local facilities and run by qualified fitness professionals.

This is a service which could tap into the nation's currently under-deployed resources of 6,000 gyms and leisure centres, staffed by more than 40,000 qualified health professionals - all of which are no more than 20 minutes from almost 90% of the population.

With all eyes turned towards the hosting of the Olympic Games in 2012 it is ironic that the expected cost of the London Olympic park which has risen 40% since the games were won in July 2005, amounts to an increase of £900m, which is just shy of the total cost the NHS spent last year treating obesity in the UK and its related lifestyle diseases.

As we seek to place our nation at the forefront of sporting excellence, creating facilities that will inspire and astound the world, we need to be mindful of the fact that our Olympic legacy should extend beyond capital investment and instead crystallise into programmes that facilitate access to sport for all. This should also involve a change in attitudes towards exercise and involve a commitment to promote the life-enhancing benefits of physical exercise. Only by doing this can we ditch the label of being the "fat man" of Europe.

Ask any doctor which is more effective, prevention or cure, and the answer will invariably be prevention, regardless of whether we are talking about programmes to reduce heart disease, drug abuse, cancer or infectious disease. And so it is with obesity. We have the tools we need to ensure that more people are more active, more often, and to trigger the behavioural and lifestyle changes required and to curtail the rapid escalation of lifestyle-related diseases.

However, by medicalising obesity to cure it, we complicate the equation and face a future of people reliant on drugs and tablets for an illness which is primarily preventable. Consumers must be more aware of the need to balance their nutrition with the exercise they take and, by increasing their understanding of the issues, we will effect long-term behavioural changes. As the great Greek physician said: "Everyone has a doctor in him or her; we just have to help it in its work."